Historical Essay © Andreas Parsch

Teledyne Ryan AQM-81 Firebolt

In the 1968/69 time frame, the USAF flight tested some modified Beech AQM-37A target drones under the Sandpiper program. The main modification was the replacement of the AQM-37's inherently dangerous liquid-fueled rocket (which used hypergolic propellants) with a hybrid unit using a solid grain fuel and a liquid oxidizer, which would not burn on contact. After the Sandpiper tests were successful, the Air Force formally started the XAQM-81A HAST (High Altitude Supersonic Target) program to develop a production target based on the AQM-37 Sandpiper configuration.

The HAST (later renamed to HAHST (High Altitude High Speed Target)) development program apparently met with some difficulties because the configuration was not finalized before the late 1970s. However, Beech's offer for a full-scale development contract was considered too expensive, and therefore the USAF called for competitive bids for HAHST development from the industry. In December 1979, the AQM-81 contract was awarded to Teledyne Ryan's Model 305 Firebolt. The first test flight of an XAQM-81A occurred in June 1983.

The Firebolt was based on the AQM-37, but used a hybrid liquid/solid rocket propulsion system as originally demonstrated in the Sandpiper program. The engine, built by the Chemical Systems Division (CSD) of United Technology, was throttleable between 0.53 kN (120 lb) and 5.3 kN (1200 lb). A ram air turbine, with an inlet below the center fuselage, pressurized the IRFNA (Inhibited Red Fuming Nitric Acid) oxidizer before it was delivered to the thrust chamber, and also provided electrical power for the missile. After air launch at about Mach 1.5 from an F-4 aircraft, the hybrid rocket could propel the XAQM-81A to speeds of more than Mach 4 at altitudes of 30000 m (100000 ft). The Firebolt could fly a pre-pregrammed course and/or respond to guidance commands from the ground. The parachute recovery system allowed either a soft landing or a mid-air retrieval.

The designation AQM-81B was allocated to a projected U.S. Navy version. This was to have support for the Navy's AN/USW-3(V) ITCS (Integrated Tracking and Control System), radar augmentation for ground tracking requirements, and a floatation gear for recovery over water. The designation AQM-81N is sometimes quoted for the Naval version, but the N suffix is unofficial.

The AQM-81 test and evaluation program was successfully completed in late 1984. However, no follow-on contract for Firebolt production was awarded, presumably because it was significantly more expensive than the simpler expendable AQM-37.

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for XAQM-81A:

[1] William Wagner, William P. Sloan: "Fireflies and other UAVs", Midland Publishing, 1992
[2] Kenneth Munson: "World Unmanned Aircraft", Jane's, 1988

Manufacturer: Teledyne-Ryan. Guidance: Command Link.

USAF

Manufacturer: Teledyne-Ryan. Liftoff Thrust: 5.290 kN (1,189 lbf). Total Mass: 558 kg (1,230 lb). Core Diameter: 0.34 m (1.11 ft). Total Length: 5.18 m (16.99 ft). Span: 1.01 m (3.31 ft). Maximum range: 519 km (322 mi). Boost Propulsion: Solid rocket. Cruise Propulsion: Storable liquid rocket. Guidance: Autopilot + Command Link. Maximum speed: 4,520 kph (2,800 mph). Ceiling: 30,500 m (100,000 ft). Development Cost $: 38.000 million. in: 1982 average dollars.

USN

Manufacturer: Teledyne-Ryan.